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Suppose that 90% of people are right-handed. What is the probability that at most 6 of a random sample of 10 people are right-handed?
It is given in the question that,
90% of the people are right handed
Let p denotes the probability of people that are right handed and q denotes the probability of people that are left handed
∴
And,
Now, by using the binomial distribution probability of having more than 6 right handed people can be given as:
Hence, the probability of having more than 6 right handed people:
= 1 – P (More than 6 people are right handed)
=
Suppose we have four boxes A, B, C and D containing coloured marbles as given below:
Box | Marble colour | ||
Red | White | Black | |
A | 1 | 6 | 3 |
B | 6 | 2 | 2 |
C | 8 | 1 | 1 |
D | 0 | 6 | 4 |
One of the boxes has been selected at random and a single marble is drawn from it. If the marble is red, what is the probability that it was drawn from box A?, box B?, box C?